Extract BSS coex 40 MHz check into a separate function

Move this implementation from check_40mhz_2g4() into a new helper
function check_bss_coex_40mhz function() so that it can be used in the
station mode case as well as the previously used AP mode case.

Signed-off-by: Sergey Matyukevich <sergey.matyukevich.os@quantenna.com>

src/common/hw_features_common.c

@@ -279,37 +279,30 @@ static int check_20mhz_bss(struct wpa_scan_res *bss, int pri_freq, int start,
 }
 
 
-int check_40mhz_2g4(struct hostapd_hw_modes *mode,
+/*
-		    struct wpa_scan_results *scan_res, int pri_chan,
+ * Returns:
-		    int sec_chan)
+ * 0: no impact
+ * 1: overlapping BSS
+ * 2: overlapping BSS with 40 MHz intolerant advertisement
+ */
+int check_bss_coex_40mhz(struct wpa_scan_res *bss, int pri_freq, int sec_freq)
 {
-	int pri_freq, sec_freq;
 	int affected_start, affected_end;
-	size_t i;
+	struct ieee802_11_elems elems;
+	int pri_chan, sec_chan;
+	int pri = bss->freq;
+	int sec = pri;
 
-	if (!mode || !scan_res || !pri_chan || !sec_chan ||
+	if (pri_freq == sec_freq)
-	    pri_chan == sec_chan)
+		return 1;
-		return 0;
-
-	pri_freq = hw_get_freq(mode, pri_chan);
-	sec_freq = hw_get_freq(mode, sec_chan);
 
 	affected_start = (pri_freq + sec_freq) / 2 - 25;
 	affected_end = (pri_freq + sec_freq) / 2 + 25;
-	wpa_printf(MSG_DEBUG, "40 MHz affected channel range: [%d,%d] MHz",
-		   affected_start, affected_end);
-	for (i = 0; i < scan_res->num; i++) {
-		struct wpa_scan_res *bss = scan_res->res[i];
-		int pri = bss->freq;
-		int sec = pri;
-		struct ieee802_11_elems elems;
 
 	/* Check for overlapping 20 MHz BSS */
-		if (check_20mhz_bss(bss, pri_freq, affected_start,
+	if (check_20mhz_bss(bss, pri_freq, affected_start, affected_end)) {
-				    affected_end)) {
+		wpa_printf(MSG_DEBUG, "Overlapping 20 MHz BSS is found");
-			wpa_printf(MSG_DEBUG,
+		return 1;
-				   "Overlapping 20 MHz BSS is found");
-			return 0;
 	}
 
 	get_pri_sec_chan(bss, &pri_chan, &sec_chan);
@@ -323,7 +316,7 @@ int check_40mhz_2g4(struct hostapd_hw_modes *mode,
 
 	if ((pri < affected_start || pri > affected_end) &&
 	    (sec < affected_start || sec > affected_end))
-			continue; /* not within affected channel range */
+		return 0; /* not within affected channel range */
 
 	wpa_printf(MSG_DEBUG, "Neighboring BSS: " MACSTR
 		   " freq=%d pri=%d sec=%d",
@@ -339,12 +332,11 @@ int check_40mhz_2g4(struct hostapd_hw_modes *mode,
 				   pri, sec, pri_chan,
 				   sec > pri ? '+' : '-',
 				   pri_freq, sec_freq);
-				return 0;
+			return 1;
 		}
 	}
 
-		ieee802_11_parse_elems((u8 *) (bss + 1), bss->ie_len, &elems,
+	ieee802_11_parse_elems((u8 *) (bss + 1), bss->ie_len, &elems, 0);
-				       0);
 	if (elems.ht_capabilities) {
 		struct ieee80211_ht_capabilities *ht_cap =
 			(struct ieee80211_ht_capabilities *)
@@ -355,9 +347,34 @@ int check_40mhz_2g4(struct hostapd_hw_modes *mode,
 			wpa_printf(MSG_DEBUG,
 				   "40 MHz Intolerant is set on channel %d in BSS "
 				   MACSTR, pri, MAC2STR(bss->bssid));
+			return 2;
+		}
+	}
+
+	return 0;
+}
+
+
+int check_40mhz_2g4(struct hostapd_hw_modes *mode,
+		    struct wpa_scan_results *scan_res, int pri_chan,
+		    int sec_chan)
+{
+	int pri_freq, sec_freq;
+	size_t i;
+
+	if (!mode || !scan_res || !pri_chan || !sec_chan ||
+	    pri_chan == sec_chan)
+		return 0;
+
+	pri_freq = hw_get_freq(mode, pri_chan);
+	sec_freq = hw_get_freq(mode, sec_chan);
+
+	wpa_printf(MSG_DEBUG, "40 MHz affected channel range: [%d,%d] MHz",
+		   (pri_freq + sec_freq) / 2 - 25,
+		   (pri_freq + sec_freq) / 2 + 25);
+	for (i = 0; i < scan_res->num; i++) {
+		if (check_bss_coex_40mhz(scan_res->res[i], pri_freq, sec_freq))
 			return 0;
-			}
-		}
 	}
 
 	return 1;

src/common/hw_features_common.h

@@ -29,6 +29,7 @@ void get_pri_sec_chan(struct wpa_scan_res *bss, int *pri_chan, int *sec_chan);
 int check_40mhz_5g(struct wpa_scan_results *scan_res,
 		   struct hostapd_channel_data *pri_chan,
 		   struct hostapd_channel_data *sec_chan);
+int check_bss_coex_40mhz(struct wpa_scan_res *bss, int pri_freq, int sec_freq);
 int check_40mhz_2g4(struct hostapd_hw_modes *mode,
 		    struct wpa_scan_results *scan_res, int pri_chan,
 		    int sec_chan);